1. Field of the Invention
The present invention is directed to an X-ray exposure apparatus of the type suited for use in digital mammography.
2. Description of the Prior Art
X-ray exposure apparatuses are known wherein the X-ray image is imaged from a luminescent screen onto an image plane with the assistance of an optical system. The luminescent screen, for example, can be the output screen of an X-ray image intensifier, and the image plane can lie in a video camera. Instead of an X-ray image intensifier, solid state image converters have recently come into use in radiology, these being composed of a matrix of detector elements whose electrical output signals are supplied to an image computer for generating an X-ray image. The luminescent screen converts the X-rays into visible light, and the solid state converter converts the visible light into corresponding electrical signals. Such a detector can, for example, be a CCD converter or a converter on the basis of amorphous, hydrated silicon.
Solid state detectors cannot yet be implemented with a size such that they can be arranged immediately behind the luminescent screen for picking up the entire X-ray image. It is therefore known to prepare digital mammography exposures with the assistance of a mosaic of solid state detectors that is shifted for filling out the interspaces between the individual detectors (IEEE Transactions on Medical Imaging, Vol. 15, No. 3, Jun. 1996, pages 260 through 267).
German OS 196 00 577 discloses a device for positioning a female breast so that it has a stable shape for diagnosis and therapy, wherein an approximately hemispherical, position-fixable receptacle shell for the breast is provided, with sensors or radiation sources being arranged around this shell. This device is primarily suitable for ultrasound image generation and for therapy. No means are provided for X-ray exposures.
German OS 41 38 659 discloses a medical X-ray image pickup system, particularly for dental exposures, wherein a strip-shaped X-ray fluorescent screen is provided from which optical fibers are conducted to solid state image pickup devices, the latter being curved. This apparatus is not suitable for the production of mammographic exposures.